Treatment of materials containing natural silk



Patented Oct, 11, 1932' UNITED GEORGE HOLLAND ELLIS, OF SPONDON, NEARDERBY, ENGLAND, ASSIGNOR T0 CELANESE CORPORATION OF AMERICA, ACORPORATION OF DELAWARE TREATMENT OF MATERIALS CONTAINING NATURAL SILKNo Drawing.

This invention relates to the treatment of fabrics or other goods ormaterials made of or containing natural silk with alkaline reagents.

It is well-known that treatment of materials containin natural silk withcaustic alkali results in de degumming materials comprising natural silkit has been the practice to temper the action of caustic alkali byaddition of other reagents such as sulphonated oil or to use instead ofcaustic alkali, alkaline reagents having a milder action, for exampleborax or sodium silicate.

I have now made the discovery that natural silk goods may be protectedagainst the action of alkaline reagents by the simultaneous presence ofcellulose esters. Provided that the latter be present in more than aninsignificant percentage, the action of the alkali is almost whollyconfined to the cellulose ester component, the natural silk remainingsubstantially unaffected. This discovery is very surprising since itwould be expected that the natural silk already degummed or degummed byreason of the alkaline reagent would be acted upon by the alkalinereagent to produce a degradation in addition to saponification or.hydrolysis of the cellulose ester. This discovery may be most usefullyapplied in the treatment of mixed materials containing both natural silkand cellulose acetate or other cellulose esters. By treating such amixed material with a .suitable alkaline reagent saponification of: thecellulose ester results with or without degumming of the natural silkbut without degradation.

In the past in degumming thenatural silk of materials comprlsinghothcellulose esters and natural silk care has been taken to avoidalkalinity suflicient to produce either degradation of the natural silkconstituent or saponification or hydrolysis of the cellulose ester.

I have found moreover that the above property may be utilized to producevarious colour efiects upon mixed materials containing both celluloseesters and natural silky For example, the material containing naturalsilk and superficially or partially saponigradation of the silk. In.

Application filed June 24, 1929, Serial No. 373,490, and in GreatBritain July 9, 1928.

fied cellulose ester may be treated with dyestufi's, for instance someacid and direct cotton dyestuffs, having an aflinity for the naturalsilk and for cellulose materials to produce shades substantially even onthe cellulose M ester and silk components.

Moreover I have found that the superficially or partially saponified orhydrolized cellulose esters retain their afiinity .for the insolublecolours especially devised for apm plication to cellulose esters andusually applied in solubilized or dispersed form, e.

the S. 'R. A: colours. By applying S1151 dyestufli's for dyeing thecellulose ester constituent of the mixed materials, diflerential 65colouration is obtainable since the'natural silk is not in general dyedby these dyestufis. Furthermore the materials treated according to thepresent invention may be dyed both with the S. R. A. type of colour and7" with the direct cotton type of colour so as to obtain a single shadeon the natural silk due to the direct cotton colour and a compound shadeon the cellulose ester component due to both types of colour. Again ifde- 75 sired the -.mixed materials treated according to the presentinvention may be coloured with acid dyestuifs which resist or onlyslightly stain cellulosic materials and this type of dye may be appliedin conjunction with any 30" tion or hydrolysis of the cellulose estermay on be employed, and furthermore salts or other electrolytes may beadded thereto as has been proposed in prior saponification'processes.,The treatment with an alkaline reagent may convenientlyand economicallybe or.

carried out in conjunction with the degumming of the natural silk bysimple addition of the suificient quantities of alkali to the customarysoap or soluble or sulphonated oil solution. Furthermore if desired dyeustuifs may be incorporated such a solution provided they are compatibletherew th,

for example the insoluble dyestuffs generally applied to celluloseesters in solubilized or dispersed form.

I have found that the best results in the saponification or hydrolysisare obtained if the liquor bath volume is adjusted so as to A wovencrepe fabric consisting of equal weights of cellulose acetate andnatural silk in the gum is suspended by means oif loops in a 1 bathcontaining 5 grams per ,litre of soap and a quaiitity of caustic sodaequal to 10% of the weight of cellulose acetate present. The bath isthen raised to 95100 C. and the goods treated for 3 hours, by which timethe cellulose acetate is saponified approximately 10%, lustre beingsimultaneously modified. The natural silk is simultaneously fullydegummed, loss in weight being normal, and handle and tensile strengthfully equal to samples -degummed by methods familiar in the art. v

The cellulose acetate portion may now be dyed with the insolubledyestuffs having selective afinity for that fibre, and the natural silkwith acid dyestuffs having little or no afinity for cellulose acetate orregenerated cellulosic fibres. Thus a blue maybe obtained on thecellulose acetate by means of di- Inethyldiamino-anthrarufin, and anorange on the natural silk with Kiton Fast Grange G. (Colour, Index No.27).

Example .9

A woven crepe fabric consisting of 1 part of degummed natural silk asweft and 2 parts of cellulose acetate as 'warp is treated at 80 C. in a5 gram per litre soap solution containing 5% caustic soda on the weightof cellulose acetate (volume 200 1) A further 2 caustic soda is addedafter 1 hour, and a similar amount again after another hour mak-Treatment is continued for %1 hour longer, after which the fabricislifted, rinsed and dried or otherwise treated as requisite. Thecellulose acetate portion has now'been saponified approximately 10% andexhibits the modified dyeing and other properties of superficially orpartially saponified cellulose acetate, whilst the natural silk retainsits characteristic properties.

' While the invention has been described above more particularly withreference to the treatment of materials consisting of natural silk andcellulose acetate it may be applied rate or the products obtained bytreatment of alkalized cellulose with esterifying agents, e. g. theproduct obtained with p-toluene sulpho-chloride and known as immunizedcot ton and to materials containing other constituents in addition tonatural silk and cellulose esters, for example cotton or other naturalcellulose material, cellulose ethers, or 4 the cellulosic type ofartificial silk, i. e. viscose, cuprammonium or nitrocelluloseartificial silk. Such other constituents may be dyed or otherwisecoloured with any of the usual dyestuffs therefor to produce furthereffects.

What I claim and desire to secure by Letters Patent is 1. In thetreatment of materials comprising natural silk with alkaline liquors,the step of protecting the natural silk against theiaction of thealkaline reagents by effect ing the treatment in the presence ofcellulose ester material.

2. In the treatment of materials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the action ofthe alkaline reagents by treating it in the form of a mixed materialwith a cellulose ester.

3. In the treatment of materials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the action ofthe alkaline reagents by treating it in the form of a mixed materialwith a cellulose ester, the reagents being sufliciently alkaline toproduce partial saponification of the cellulose ester.

4. In the degumming of materials comprising natural silk with alkalineliquors, the

.step of protecting the natural silk against the action of the alkalinereagents bytreating it in the form of a mixed material with a celluloseester.

5. In the'treatment of materials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the action ofthe alkaline reagents by effecting the treatment'in the presence ofcellulose acetate material.

6. In the treatment of materials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the action ofthe alkaline reagents by treating it in the form of a mixed materialwith cellulose acetate. 7. In the treatment of materials comprisingnaturalsilk with alkaline liquors, the step of protecting the naturalsilk against the action of the alkaline reagents by treating it in theform of a mixed material with llll aeeaere ciently alkaline to producepartial saponification of the cellulose acetate.

8. In the degumming of materials comprising natural silk with alkalineliquors, the

step of protecting the natural silk against.

the action of the alkaline reagents. by treating it in the form (if amixed material with cellulose acetate.

9. In the treatment ofmaterials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the action ofthe alkaline reagents by treating it in the form of a mixed materialwith a cellulose ester and subsequently colouring the material with adyestuff having an afiinity for at least one of the constituents of themixed material.

10. In the treatment of materials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the action ofthe alkaline reagents by treating it in the form of a mixed materialwith cellulose acetate and subsequently colouring the material with adyestufl having an afiinity for at least one of the constituents of themixed material. 11. In the treatment of materials comprising naturalsilk with alkaline liquors, the step of protecting the natural silkagainst the action of the alkaline reagents by treating it in the formof a mixed material with a cellulose ester, the reagents beingsufficiently alkaline to produce partial saponification of the celluloseester and subsequently colouring the material with a dyestuif having anafiinity for both of the constituents of the mixed material.

12. In the treatment of materials comprising natural silk with alkalineliquors, the step of protecting the natural silk against the actlon ofthe alkaline reagents by treating it in the form of a. mixed materialwith cellulose icetate, the reagents being sufficiently alkaline toproduce partialsaponification of the cellulose acetate and subsequentlycolouring the material with a dyestufi having an aflinity for both ofthe constituents of the mixed material.

In testimony whereof I have hereunto subscribed my name.

GEORGE HOLLAND- ELLIS.

